Effects of boehmite synthesis conditions on the epoxidation of styrene

Abstract

The influence of synthesis conditions on the properties of nanocrystalline boehmite catalysts was studied for styrene epoxidation reaction in liquid phase. At hydrothermal synthesis of boehmite, effects of pH, aging time and precursor aluminum salts were studied by X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA) and total surface area. Characterization results showed that boehmite samples were in the nanosize range and single-phase with high crystallinity. Styrene epoxidation reaction in liquid phase was performed over boehmite catalysts at 80 degrees C in ethanol, using 30% aqueous hydrogen peroxide solution and urea + 30% aqueous hydrogen peroxide solution as oxidants. The progress of the reaction was followed by gas chromatography (GC). Higher styrene conversion and higher epoxide selectivities were achieved when urea was mixed with H(2)O(2) solution. Boehmite catalyst samples aged for 8 h resulted in higher epoxide selectivities.